1. Field of the Invention
The present invention relates to zoom control systems and, more particularly, to a zoom lens control system for controlling the direction and speed of a zoom operation.
2. Description of the Related Art
Zooming devices generally include a switch commonly termed a zooming switch, which determines the shortening or lengthening of the focal distance according to the direction of zooming by means of a multiplying lens group. It is also known to include a second switch called a zooming speed switch for shifting the zooming speed. Use of both a zooming direction switch and a zooming speed stitch in a zooming device is disadvantageous since it requires multiple actuations by the zooming device operator.
In U.S. Pat. No. 4,445,757, a zooming device is proposed in which the direction and speed of zooming by means of a multiple lens group is achieved by use of a special rocker type switch. The rocker switch includes a plurality of successively operable switches and a flexible contact on each side of the center of rotation. The rocker can be turned in either direction to operate the first one of the plurality of switches so as to obtain a zooming operation in the corresponding direction and at a predetermined speed. The zooming speed can be changed to a next speed when a second one of the switches is operated by further turning of the rocker and flexing of the corresponding flexible contact. The '757 zooming device is disadvantageous and undesirable in a low cost zooming application since it requires the use of a special rocker switch which is mechanically complex and costly. A further disadvantage of the '757 zooming device is that the special rocker switch is unreliable in that it includes a flexible metal contact susceptible to metal fatigue and failure.
It would thus be desirable to provide a zoom control system that is simple, cost effective, and reliable.